<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>伸缩菜单项</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }

        li{
            list-style: none;
        }

        .box{
            width: 500px;
            height: 300px;
            border: 1px solid #EEE;
            margin: 200px auto;
        }

        .box ul{
            width: 100%;
            display: flex;
            flex-direction: row;
            justify-content: space-around;
        }

        .box ul li{
            flex: 1;
            height: 40px;
            text-align: center;
            line-height: 40px;
            background-color: lightcoral;
            border-right: 2px solid black;
        }

        .box ul li:last-child{
            border-right: none;
        }


        .f{
            width: 500px;
            height: 500px;
            background-color: cadetblue;
            margin: auto;
            /* 伸缩盒子 */
            display: flex;
            /* 水平居中 */
            justify-content: center;
            /* 垂直居中 */
            align-items: center;
        }

        .f .s{
            width: 200px;
            height: 200px;
            background-color: lightcoral;
        }
    </style>
</head>
<body>
    <div class="box">
        <ul>
            <li>英雄列表</li>
            <li>英雄详情</li>
            <li>物品列表</li>
            <li>技能列表</li>
            <li>符文列表</li>
        </ul>
    </div>

    <br><br><br>

    <div class="f">
        <div class="s"></div>
    </div>
</body>
</html>